/*! \file fat.h \brief FAT16/32 file system driver. */
//*****************************************************************************
//
// File Name : 'fat.h'
// Title : FAT16/32 file system driver
// Author : Pascal Stang
// Date : 11/07/2000
// Revised : 12/12/2000
// Version : 0.3
// Target MCU : ATmega103 (should work for Atmel AVR Series)
// Editor Tabs : 4
//
// NOTE: This code is currently below version 1.0, and therefore is considered
// to be lacking in some functionality or documentation, or may not be fully
// tested. Nonetheless, you can expect most functions to work.
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
#ifndef FAT_H
#define FAT_H
#include "global.h"
// Some useful cluster numbers
#define MSDOSFSROOT 0 // cluster 0 means the root dir
#define CLUST_FREE 0 // cluster 0 also means a free cluster
#define MSDOSFSFREE CLUST_FREE
#define CLUST_FIRST 2 // first legal cluster number
#define CLUST_RSRVD 0xfffffff6 // reserved cluster range
#define CLUST_BAD 0xfffffff7 // a cluster with a defect
#define CLUST_EOFS 0xfffffff8 // start of eof cluster range
#define CLUST_EOFE 0xffffffff // end of eof cluster range
#define FAT12_MASK 0x00000fff // mask for 12 bit cluster numbers
#define FAT16_MASK 0x0000ffff // mask for 16 bit cluster numbers
#define FAT32_MASK 0x0fffffff // mask for FAT32 cluster numbers
// Partition Type used in the partition record
#define PART_TYPE_UNKNOWN 0x00
#define PART_TYPE_FAT12 0x01
#define PART_TYPE_XENIX 0x02
#define PART_TYPE_DOSFAT16 0x04
#define PART_TYPE_EXTDOS 0x05
#define PART_TYPE_FAT16 0x06
#define PART_TYPE_NTFS 0x07
#define PART_TYPE_FAT32 0x0B
#define PART_TYPE_FAT32LBA 0x0C
#define PART_TYPE_FAT16LBA 0x0E
#define PART_TYPE_EXTDOSLBA 0x0F
#define PART_TYPE_ONTRACK 0x33
#define PART_TYPE_NOVELL 0x40
#define PART_TYPE_PCIX 0x4B
#define PART_TYPE_PHOENIXSAVE 0xA0
#define PART_TYPE_CPM 0xDB
#define PART_TYPE_DBFS 0xE0
#define PART_TYPE_BBT 0xFF
struct partrecord // length 16 bytes
{
BYTE prIsActive; // 0x80 indicates active partition
BYTE prStartHead; // starting head for partition
WORD prStartCylSect; // starting cylinder and sector
BYTE prPartType; // partition type (see above)
BYTE prEndHead; // ending head for this partition
WORD prEndCylSect; // ending cylinder and sector
DWORD prStartLBA; // first LBA sector for this partition
DWORD prSize; // size of this partition (bytes or sectors ?)
};
struct partsector
{
CHAR psPartCode[512-64-2]; // pad so struct is 512b
BYTE psPart[64]; // four partition records (64 bytes)
BYTE psBootSectSig0; // two signature bytes (2 bytes)
BYTE psBootSectSig1;
#define BOOTSIG0 0x55
#define BOOTSIG1 0xaa
};
// Format of a boot sector. This is the first sector on a DOS floppy disk
// or the first sector of a partition on a hard disk. But, it is not the
// first sector of a partitioned hard disk.
struct bootsector33 {
BYTE bsJump[3]; // jump inst E9xxxx or EBxx90
CHAR bsOemName[8]; // OEM name and version
CHAR bsBPB[19]; // BIOS parameter block
CHAR bsDriveNumber; // drive number (0x80)
CHAR bsBootCode[479]; // pad so struct is 512b
BYTE bsBootSectSig0; // boot sector signature byte 0x55
BYTE bsBootSectSig1; // boot sector signature byte 0xAA
#define BOOTSIG0 0x55
#define BOOTSIG1 0xaa
};
struct extboot {
CHAR exDriveNumber; // drive number (0x80)
CHAR exReserved1; // reserved
CHAR exBootSignature; // ext. boot signature (0x29)
#define EXBOOTSIG 0x29
CHAR exVolumeID[4]; // volume ID number
CHAR exVolumeLabel[11]; // volume label
CHAR exFileSysType[8]; // fs type (FAT12 or FAT16)
};
struct bootsector50 {
BYTE bsJump[3]; // jump inst E9xxxx or EBxx90
CHAR bsOemName[8]; // OEM name and version
CHAR bsBPB[25]; // BIOS parameter block
CHAR bsExt[26]; // Bootsector Extension
CHAR bsBootCode[448]; // pad so structure is 512b
BYTE bsBootSectSig0; // boot sector signature byte 0x55
BYTE bsBootSectSig1; // boot sector signature byte 0xAA
#define BOOTSIG0 0x55
#define BOOTSIG1 0xaa
};
struct bootsector710 {
BYTE bsJump[3]; // jump inst E9xxxx or EBxx90
CHAR bsOEMName[8]; // OEM name and version
CHAR bsBPB[53]; // BIOS parameter block
CHAR bsExt[26]; // Bootsector Extension
CHAR bsBootCode[418]; // pad so structure is 512b
BYTE bsBootSectSig2; // 2 & 3 are only defined for FAT32?
BYTE bsBootSectSig3;
BYTE bsBootSectSig0; // boot sector signature byte 0x55
BYTE bsBootSectSig1; // boot sector signature byte 0xAA
#define BOOTSIG0 0x55
#define BOOTSIG1 0xaa
#define BOOTSIG2 0
#define BOOTSIG3 0
};
/***************************************************************/
/***************************************************************/
// BIOS Parameter Block (BPB) for DOS 3.3
struct bpb33 {
WORD bpbBytesPerSec; // bytes per sector
BYTE bpbSecPerClust; // sectors per cluster
WORD bpbResSectors; // number of reserved sectors
BYTE bpbFATs; // number of FATs
WORD bpbRootDirEnts; // number of root directory entries
WORD bpbSectors; // total number of sectors
BYTE bpbMedia; // media descriptor
WORD bpbFATsecs; // number of sectors per FAT
WORD bpbSecPerTrack; // sectors per track
WORD bpbHeads; // number of heads
WORD bpbHiddenSecs; // number of hidden sectors
};
// BPB for DOS 5.0
// The difference is bpbHiddenSecs is a short for DOS 3.3,
// and bpbHugeSectors is not present in the DOS 3.3 bpb.
struct bpb50 {
WORD bpbBytesPerSec; // bytes per sector
BYTE bpbSecPerClust; // sectors per cluster
WORD bpbResSectors; // number of reserved sectors
BYTE bpbFATs; // number of FATs
WORD bpbRootDirEnts; // number of root directory entries
WORD bpbSectors; // total number of sectors
BYTE bpbMedia; // media descriptor
WORD bpbFATsecs; // number of sectors per FAT
WORD bpbSecPerTrack; // sectors per track
WORD bpbHeads; // number of heads
DWORD bpbHiddenSecs; // # of hidden sectors
// 3.3 compat ends here
DWORD bpbHugeSectors; // # of sectors if bpbSectors == 0
};
// BPB for DOS 7.10 (FAT32)
// This one has a few extensions to bpb50.
struct bpb710 {
WORD bpbBytesPerSec; // bytes per sector
BYTE bpbSecPerClust; // sectors per cluster
WORD bpbResSectors; // number of reserved sectors
BYTE bpbFATs; // number of FATs
WORD bpbRootDirEnts; // number of root directory entries
WORD bpbSectors; // total number of sectors
BYTE bpbMedia; // media descriptor
WORD bpbFATsecs; // number of sectors per FAT
WORD bpbSecPerTrack; // sectors per track
WORD bpbHeads; // number of heads
DWORD bpbHiddenSecs; // # of hidden sectors
// 3.3 compat ends here
DWORD bpbHugeSectors; // # of sectors if bpbSectors == 0
// 5.0 compat ends here
DWORD bpbBigFATsecs;// like bpbFATsecs for FAT32
WORD bpbExtFlags; // extended flags:
#define FATNUM 0xf // mask for numbering active FAT
#define FATMIRROR 0x80 // FAT is mirrored (like it always was)
WORD bpbFSVers; // filesystem version
#define FSVERS 0 // currently only 0 is understood
DWORD bpbRootClust; // start cluster for root directory
WORD bpbFSInfo; // filesystem info structure sector
WORD bpbBackup; // backup boot sector
// There is a 12 byte filler here, but we ignore it
};
// ***************************************************************
// * byte versions of the above structs *
// ***************************************************************
// BIOS Parameter Block (BPB) for DOS 3.3
struct byte_bpb33 {
CHAR bpbBytesPerSec[2]; // bytes per sector
CHAR bpbSecPerClust; // sectors per cluster
CHAR bpbResSectors[2]; // number of reserved sectors
CHAR bpbFATs; // number of FATs
CHAR bpbRootDirEnts[2]; // number of root directory entries
CHAR bpbSectors[2]; // total number of sectors
CHAR bpbMedia; // media descriptor
CHAR bpbFATsecs[2]; // number of sectors per FAT
CHAR bpbSecPerTrack[2]; // sectors per track
CHAR bpbHeads[2]; // number of heads
CHAR bpbHiddenSecs[2]; // number of hidden sectors
};
// BPB for DOS 5.0
// The difference is bpbHiddenSecs is a short for DOS 3.3,
// and bpbHugeSectors is not in the 3.3 bpb.
struct byte_bpb50 {
CHAR bpbBytesPerSec[2]; // bytes per sector
CHAR bpbSecPerClust; // sectors per cluster
CHAR bpbResSectors[2]; // number of reserved sectors
CHAR bpbFATs; // number of FATs
CHAR bpbRootDirEnts[2]; // number of root directory entries
CHAR bpbSectors[2]; // total number of sectors
CHAR bpbMedia; // media descriptor
CHAR bpbFATsecs[2]; // number of sectors per FAT
CHAR bpbSecPerTrack[2]; // sectors per track
CHAR bpbHeads[2]; // number of heads
CHAR bpbHiddenSecs[4]; // number of hidden sectors
CHAR bpbHugeSectors[4]; // # of sectors if bpbSectors == 0
};
// BPB for DOS 7.10 (FAT32).
// This one has a few extensions to bpb50.
struct byte_bpb710 {
BYTE bpbBytesPerSec[2]; // bytes per sector
BYTE bpbSecPerClust; // sectors per cluster
BYTE bpbResSectors[2]; // number of reserved sectors
BYTE bpbFATs; // number of FATs
BYTE bpbRootDirEnts[2]; // number of root directory entries
BYTE bpbSectors[2]; // total number of sectors
BYTE bpbMedia; // media descriptor
BYTE bpbFATsecs[2]; // number of sectors per FAT
BYTE bpbSecPerTrack[2]; // sectors per track
BYTE bpbHeads[2]; // number of heads
BYTE bpbHiddenSecs[4]; // # of hidden sectors
BYTE bpbHugeSectors[4]; // # of sectors if bpbSectors == 0
BYTE bpbBigFATsecs[4]; // like bpbFATsecs for FAT32
BYTE bpbExtFlags[2]; // extended flags:
BYTE bpbFSVers[2]; // filesystem version
BYTE bpbRootClust[4]; // start cluster for root directory
BYTE bpbFSInfo[2]; // filesystem info structure sector
BYTE bpbBackup[2]; // backup boot sector
// There is a 12 byte filler here, but we ignore it
};
// FAT32 FSInfo block.
struct fsinfo {
BYTE fsisig1[4];
BYTE fsifill1[480];
BYTE fsisig2[4];
BYTE fsinfree[4];
BYTE fsinxtfree[4];
BYTE fsifill2[12];
BYTE fsisig3[4];
BYTE fsifill3[508];
BYTE fsisig4[4];
};
/***************************************************************/
/***************************************************************/
// Structure of a dos directory entry.
struct direntry {
BYTE deName[8]; // filename, blank filled
#define SLOT_EMPTY 0x00 // slot has never been used
#define SLOT_E5 0x05 // the real value is 0xe5
#define SLOT_DELETED 0xe5 // file in this slot deleted
BYTE deExtension[3]; // extension, blank filled
BYTE deAttributes; // file attributes
#define ATTR_NORMAL 0x00 // normal file
#define ATTR_READONLY 0x01 // file is readonly
#define ATTR_HIDDEN 0x02 // file is hidden
#define ATTR_SYSTEM 0x04 // file is a system file
#define ATTR_VOLUME 0x08 // entry is a volume label
#define ATTR_LONG_FILENAME 0x0f // this is a long filename entry
#define ATTR_DIRECTORY 0x10 // entry is a directory name
#define ATTR_ARCHIVE 0x20 // file is new or modified
BYTE deLowerCase; // NT VFAT lower case flags
#define LCASE_BASE 0x08 // filename base in lower case
#define LCASE_EXT 0x10 // filename extension in lower case
BYTE deCHundredth; // hundredth of seconds in CTime
BYTE deCTime[2]; // create time
BYTE deCDate[2]; // create date
BYTE deADate[2]; // access date
WORD deHighClust; // high bytes of cluster number
BYTE deMTime[2]; // last update time
BYTE deMDate[2]; // last update date
WORD deStartCluster; // starting cluster of file
DWORD deFileSize; // size of file in bytes
};
// number of directory entries in one sector
#define DIRENTRIES_PER_SECTOR 0x10
// Structure of a Win95 long name directory entry
struct winentry {
BYTE weCnt;
#define WIN_LAST 0x40
#define WIN_CNT 0x3f
BYTE wePart1[10];
BYTE weAttributes;
#define ATTR_WIN95 0x0f
BYTE weReserved1;
BYTE weChksum;
BYTE wePart2[12];
WORD weReserved2;
BYTE wePart3[4];
};
#define WIN_CHARS 13 // Number of chars per winentry
// Maximum filename length in Win95
// Note: Must be < sizeof(dirent.d_name)
#define WIN_MAXLEN 255
// This is the format of the contents of the deTime field in the direntry
// structure.
// We don't use bitfields because we don't know how compilers for
// arbitrary machines will lay them out.
#define DT_2SECONDS_MASK 0x1F // seconds divided by 2
#define DT_2SECONDS_SHIFT 0
#define DT_MINUTES_MASK 0x7E0 // minutes
#define DT_MINUTES_SHIFT 5
#define DT_HOURS_MASK 0xF800 // hours
#define DT_HOURS_SHIFT 11
// This is the format of the contents of the deDate field in the direntry
// structure.
#define DD_DAY_MASK 0x1F // day of month
#define DD_DAY_SHIFT 0
#define DD_MONTH_MASK 0x1E0 // month
#define DD_MONTH_SHIFT 5
#define DD_YEAR_MASK 0xFE00 // year - 1980
#define DD_YEAR_SHIFT 9
// Prototypes
unsigned char fatInit( unsigned char device);
unsigned int fatClusterSize(void);
unsigned long fatGetDirEntry(unsigned int entry, unsigned int count);
unsigned long fatGetFilesize(void);
char* fatGetFilename(void);
char* fatGetDirname(void);
void fatLoadCluster(unsigned long cluster, unsigned char *buffer);
unsigned long fatNextCluster(unsigned long cluster);
#endif